The calculated distance (air line) between Ganghwa-gun and Sariwŏn is approximately 66 miles respectively 106 kilometers.
By car or train, the actual journey to Sariwŏn is certainly longer, as only the direct route (as the crow flies) between Ganghwa-gun and Sariwŏn has been calculated here.
Air line (approximately)
106 kilometers
57 nautical miles